藏族成年男子膳食中锌的吸收状况研究

目的了解藏族成年男子膳食中锌的吸收利用,为修订膳食营养素参考摄入量(DRIs)和改善锌的营养状况提供理论依据。方法在营养调查的基础上设计出代表性的3d食谱,选择13名18~19岁的藏族健康男子给予试验膳进行14d的代谢平衡实验,收集试验期受试者的膳食、饮水、粪便、尿液样品,采用火焰原子吸收光谱法测定各样品中锌的含量,计算锌的表观吸收率、表观利用率。结果锌的表观吸收率为24·15%,与现行的DRIs的制订依据估计值接近;表观利用率为7·61%。结论代表性膳食中锌的摄入量能满足受试者的需要量。     

宁夏吴忠市职业技术学院学生膳食调查

目的了解职业技术学院在校学生营养状况，促进平衡膳食、合理营养，为职业技术学院制订学生科学食谱提供依据。方法采用称量记帐法对吴忠市职业技术学院349名学生进行膳食调查。结果蛋白质摄入量占《中国居民膳食营养素参考摄入量，DRIs》的69％左右；能量摄入分布中，蛋白质供能不足，仅占9．4％(标准为12％～14％)；动物脂肪摄入量偏低；钙摄入量占DRIs的45％左右，严重缺乏；核黄素摄入量为DRIs的53％左右，维生素A摄入量占DRIs的65％左右；铁、硫胺素、尼克酸以及维生素C摄入量大于DRIs。结果吴忠市职业技术学院学生膳食结构不合理，应增加蛋白质、矿物质、钙和维生素A、B2的摄入量。     

彝族成年男子膳食中铁、锌、钙的生物利用研究

目的:评价彝族成年男子膳食中铁、锌和钙的生物利用情况,为防治该人群矿物质缺乏病提供基础信息。方法:以代谢平衡法于现场对12名20~22岁彝族世居地的成年男子进行14d试验。试验开始,收集对象空腹血,检测血红蛋白、红细胞压积、血清铁蛋白、血浆锌和钙浓度。试验期间,收集4~12d试验膳及摄入试验膳后排出的粪便和尿样。应用火焰原子吸收法测定膳食、粪便和尿中三种矿物质的含量,分别计算出它们的表观吸收率、平衡状态和表观利用率。结果:彝族成年男子代表性膳食中铁、锌和钙的表观吸收率(%)分别为15.8±6.2、24.5±4.1、32.3±9.7;表观利用率(%)分别为1.9±5.7、12.8±4.3、5.5±15.9。平衡试验显示铁,锌,钙均为平衡,但钙的变动范围较大。结论:膳食中铁、锌摄入量能满足试验对象的需要量,而钙的摄入量则不能满足其需要量。三种矿物质的表观吸收率与表观利用率基本上与我国正常人相同。建议彝族居民增加钙含量高的食物摄入量,以预防钙缺乏。     

453名大学生膳食调查

目的　了解温州市高校学生现时营养状况 ,并针对出现的问题提出改进措施。　方法　采用 2 4h膳食记录及称重法连续 4d调查温州市某高校 4 5 3名大学生的膳食消费结构。　结果　男生热能的摄入占参考摄入量 (DRIs)的 95 .7% ,达到DRIs的要求 ;女生热能的摄入量为DRIs的 84 .1% ,基本满足需要。蛋白质摄入量男生平均为 71.2g ,达DRIs的 94 .9% ;女生平均 6 3.8g达DRIs的 98.2 %。男女生铁的摄入量占DRIs10 8.7%和 92 .5 %。钙、锌及多种维生素摄入量均不足。　结论　必须加强膳食指导 ,调整膳食结构 ,以提高矿物质、维生素等摄入量     

湖南、湖北等省成年人膳食锌吸收率分析

目的 评价我国湖南、湖北等省成年人膳食结构中Zn的吸收率,为我国不同人群、不同膳食结构的Zn吸收率研究提供参考资料.方法 采用67ZnSO4锌稳定性同位素示踪法,以稀土元素镱(Yb)为粪便回收标记物,进行现场人体代谢实验.受试者为健康成年男子和育龄妇女各10名,一次性口服4.00 mg 67ZnSO4和1.00mg YbCl3,粪便监测法收集排出粪样;电感耦合等离子体质谱仪(ICP-MS)测定粪样中67Zn/66Zn比值,原子吸收火焰分光光度法(AAS)测定粪样总Zn,计算膳食Zn吸收率.结果 在不同膳食结构下,成年男子Zn表观吸收率为28.4%,真吸收率为30.3%;育龄妇女Zn表观吸收率为26.8%,真吸收率为30.9%.结果 湖南、湖北等省份膳食结构中zn的吸收率高于我国现行Zn的膳食营养参考摄入量(DRIs)(25%的估计值).     

银川市某私立学校学生膳食营养状况

目的了解私立学校学生膳食营养状况，为改善学生膳食结构提供科学依据。方法用记帐法和称量法调查某私立学校住宿学生1007名的膳食情况。结果平均每人每日能量和各种营养素摄入量为：能量13．05Mj（3120kcal），蛋白质85．4g，脂肪92.6g，碳水化合物486.2g。蛋白质、脂肪、碳水化合物供能比分别为10.96％，26．64％，62．30％，蛋白质供能占总能量比例低于12％。常量及微量元素中钾、钠、磷、镁、铁、铜、锰及维生素PP均达《中国居民膳食营养素参考摄入量》（DRIs）要求，但维生素A、维生素B1、维生素C、维生素E、钙、锌、硒摄入量不足。结论应加强平衡膳食和合理营养的教育，逐步改善学生的营养状况。     

钙的合理补充——我国人口钙营养状况

我国1992年全国第3次营养抽样调查结果表明，我国居民平均钙摄入量为405．4mg／d，其中城市居民为457．9mg／d、农村为378．2mg／d，分别占我国营养学会推荐的每日膳食中钙供给量的49．2％、53．3％及47．1％。在城市人口中，51％的男性和60％的女性的钙摄入量未达到每日膳食钙供给量的50％，达到每日膳食钙供给量的人数还不及10％；     

河南省大学生膳食营养状况分析

目的了解河南省大学生的膳食营养状况，为高校膳食营养健康教育提供依据。方法采用自行设计的膳食知识和行为问卷，对河南省部分高校656名19-22岁大学生的生活方式进行问卷调查，采用24h膳食记录连续4d调查膳食营养状况。结果0．8％的大学生不吃早餐，23．6％吃早餐但无规律。大学生的蛋白质摄入量超标，但优质蛋白摄入量不足。男生钙摄入量为433mg／d，女生为427m/d，均严重不足。结论大学生膳食营养知识欠缺，膳食结构不合理。在高校开展有针对性的膳食营养健康教育十分必要。     

厦门市两所中学学生膳食营养状况

目的：了解厦门市中学生营养状况并针对问题提出改进措施，以便为中学生提供合理的膳食营养。方法：采用24h膳食记录法和称重法，连续调查3d学生膳食状况，计算每人每日能量和营养素摄入量，与推荐摄入量进行比较。结果：男生能量摄入量占推荐摄入量为73．38％，女生为74．00％；蛋白质摄入量占推荐摄入量男生为87．88％，女生为77．13％；钙摄入量严重不足，男生仅为推荐摄入量的24．70％，女生为27．10％；视黄醇、维生素B1、维生素B2、维生素C和锌、铁也存在不同程度的摄入不足。结论：应对学生进行营养教育，提高早餐质量，增加副食摄入，补充牛奶。     

武警某军校学员和战士膳食营养调查

目的：为了解武警军校学员和战士的膳食营养状况，提出膳食营养建议，保障官兵身体健康。方法：采用3d膳食称量法进行膳食调查，按标准方法进行体格检查，对其中79名学员和95名战士进行血红蛋白、血钙、血铁和尿液维生素C测定。结果：学员和战士的膳食以粮食和蔬菜为主，蛋白质摄入量仅达军标的75．3％和72．8％；油脂摄入量分别为军标的220．0％和202．0％；多种维生素及元素钙摄入量不足，不能满足机体需要。结论：两单位膳食能量供应基本达标，但膳食结构欠合理，食物品种单一。应调整膳食结构，提高动物类食品和大豆及其制品的供应，并增加食物品种，以满足机体对维生素和矿物元素的需求。     

Iron status in Swedish teenage girls: impact of low dietary iron bioavailability

OBJECTIVE: Although it is well known that bioavailability of iron in the diet is important, it has not been fully elucidated in practice. We investigated iron intake and iron absorption in the ordinary diet of free-living individuals in relation to iron status and assessed iron requirements. METHODS: From a total of 1245 adolescent boys and girls included in the G?teborg Adolescence Study of food habits, 28 adolescent girls registered their food intake during 7 d. Iron intake was assessed on the basis of these 7-d dietary records. Iron absorption was calculated using an algorithm including enhancing and inhibiting dietary factors on iron absorption in relation to individual iron status. RESULTS: Available iron intake was 11.5 +/- 2.8 mg/d (mean +/- SD). The proportion of girls with an iron intake below the Nordic nutrition recommendations was 85% (n = 24). Calculated iron absorption was 1.09 +/- 0.59 mg/d (mean +/- SD). Only four girls satisfied their estimated individual iron requirement concerning the absorbed amount of iron. Iron depletion (serum ferritin concentration < or = 15 microg/L) was present in 10 girls (36%), 2 of whom were also anemic (hemoglobin concentration < or = 120 g/L). CONCLUSION: Swedish adolescent girls seemed to have difficulties satisfying their iron requirement in terms of absorbed amount. The data support the view that iron intake and bioavailability of dietary iron is important when evaluating whether iron requirements have been met.     

代谢平衡法与粪便监测法评价藏族成年男子膳食锌吸收率的比较

目的:比较代谢平衡法(MB)和粪便监测法(FM)评价藏族成年男子膳食锌(Zn)吸收率。方法:进行14d人体现场代谢试验,受试者于D5晚一次性口服浓集67Zn的稳定性同位素示踪剂4.0mg及稀土元素镱(Yb)1.0mg,口服卡红标记、并收集D4~12的粪便和尿液样品,同时收集膳食、饮水样品;用感耦等离子体质谱仪测定粪样67Zn/68Zn的比值,并用原子吸收分光光度计分析所收集样品中的锌含量,比较用两种方法测定该人群膳食Zn吸收率的结果。结果:MB和FM评价藏族成年男子膳食Zn吸收率分别为(23.8±3.9)%、(21.4±4.3)%,二者的差异(配对t检验)和相关性(Pearson)均有统计学意义;未吸收的Zn示踪剂和Yb经胃肠道排出情况几乎一致,主要在口服后5d内排出。结论:14d代谢试验评价膳食Zn吸收率时,MB略高于FM,后者的试验期可依据Yb的排出情况缩短至4~5d。两种方法评价的结果都表明藏族成年男子膳食Zn吸收尚可。     

补钙对12～17岁青少年锌、铁吸收率的影响

目的通过代谢平衡实验探讨补钙对中国青春期少年锌、铁吸收率的影响。方法从320名参加1年补钙实验的4组12~17岁少年中,每组随机抽取男、女生各10人,共80人。采用代谢平衡的方法,收集研究对象10天内摄入的食品、排出的粪便和尿液样品,用电感耦合等离子体发射光谱法测定样品中的钙、铁、锌含量。结果不同补钙组之间钙摄入量有差异,但铁、锌摄入量差异无显著性。不同补钙组之间钙、铁、锌的表观吸收率差异无显著性。男生钙、铁、锌的表观吸收率平均为69.4%、12.5%和29.9%,女生的分别为46.4%、20.9%和35.3%。铁的表观吸收率与青春发育水平有关。男生钙摄入量为600~800mg/d时,钙、铁、锌的表观吸收率均处于相对较高水平(75.3%、23.2%和36.4%)。结论钙摄入量低于1400mg/d时,不影响12~17岁少年锌、铁的吸收率。当男生钙摄入量为600~800mg/d时,更有助于钙、铁、锌的吸收。     

Iron absorption in male C282Y heterozygotes

BACKGROUND: The suggestion that carriers of the HFE C282Y mutation absorb nonheme iron more efficiently than do carriers of the wild type has public health implications for countries where the C282Y mutation is common and foods are fortified with iron. OBJECTIVE: We investigated the effect of C282Y heterozygosity on nonheme-iron absorption from a diet high in bioavailable iron and from iron-fortified cereals. DESIGN: The subjects were recruited from a parallel study investigating the relation between HFE mutations, habitual diet, and iron status. Iron absorption was measured in 15 wild-type carriers and 15 C282Y heterozygotes aged >/=40 y. Each subject consumed 3 meals of high iron bioavailability (labeled with Fe-57) for 2 d and 2 meals with fortified cereal products (labeled with Fe-54) for the next 3 d. Iron absorption was measured from isotope incorporation into red blood cells 14 d after the last labeled meal and was corrected for utilization of absorbed iron by means of an intravenous infusion of Fe-58. RESULTS: Absorption of Fe-57 with the high-iron-bioavailability diet was 6.8 +/- 6.8% (0.6 +/- 0.6 mg/d) in the wild-type carriers and 7.6 +/- 3.2% (0.7 +/- 0.3 mg/d) in the C282Y heterozygotes. Absorption of Fe-54 with cereal products was 4.9 +/- 2.0% (0.7 +/- 0.3 mg/d) in the wild-type carriers and 5.3 +/- 1.3% (0.8 +/- 0.2 mg/d) in the C282Y heterozygotes. CONCLUSIONS: There was no overall significant difference between C282Y heterozygotes and wild-type men in iron absorption from either dietary nonheme iron or fortified cereal products.     

Absorption and loss of iron in toddlers are highly correlated

For estimating the requirements for dietary iron, it is important to know the amount of iron that is lost from the body. Inevitable losses of iron have been determined in adult humans but not in infants or children. We administered (58)Fe, the least abundant stable isotope of iron, to free-living infants at 168 d of age (5.6 mo) and followed them to age 26 mo. There was no dietary restriction after isotope administration. Blood was obtained at regular intervals for determination of isotopic enrichment and indices of iron status. We estimated the quantity of circulating iron, noncirculating active iron, and storage iron at each age. The administered isotope equilibrated with total body iron by 13 mo of age. From 13 to 26 mo of age, we estimated inevitable loss and absorption of iron from the change in tracer abundance in circulating iron. The rate of decrease of tracer abundance was proportional to addition of tracee, i.e., absorption of iron. Conversely, the rate of decrease in quantity of tracer was proportional to removal of tracee, i.e., loss of iron. From 13 to 26 mo of age, iron absorption was (mean +/- SD) 0.49 +/- 0.13 mg/d and inevitable iron loss was 0.25 +/- 0.12 mg/d. Intersubject variability of iron loss and iron absorption was high, and iron loss and absorption were highly correlated (r = 0.789, P < 0.001). Iron stores were low throughout the study and decreased significantly from 13 to 26 mo of age, suggesting that iron absorption from the diet was inadequate to maintain or increase iron nutritional status. The data suggest that, in this cohort, which may be representative, the intake of bioavailable iron from 13 to 26 mo of age was insufficient to maintain iron nutritional status.     

Iron absorption in breast-fed infants: effects of age,iron status,iron supplements,and complementary foods

BACKGROUND: Iron supplements are often recommended for older breast-fed infants, but little is known about factors affecting iron absorption from human milk or supplements. OBJECTIVE: We investigated the effects of age, iron status, and iron intake on iron absorption in healthy, term, breast-fed infants. DESIGN: Twenty-five infants were randomly assigned to receive either 1) iron supplements (1 mg x kg(-1) x d(-1)) from 4 to 9 mo of age, 2) placebo from 4 to 6 mo and iron supplements from 6 to 9 mo, or 3) placebo from 4 to 9 mo. Infants were exclusively breast-fed to 6 mo and partially breast-fed to 9 mo of age. Iron absorption was assessed by giving (58)Fe with mother's milk at 6 and 9 mo. Blood samples were obtained at 4, 6, and 9 mo, and complementary food intake was recorded at 9 mo. RESULTS: At 6 mo, mean (+/-SD) fractional iron absorption from human milk was relatively low (16.4 +/- 11.4%), with no significant difference between iron-supplemented and unsupplemented infants. At 9 mo, iron absorption from human milk remained low in iron-supplemented infants (16.9 +/- 9.3%) but was higher (P = 0.01) in unsupplemented infants (36.7 +/- 18.9%). Unexpectedly, iron absorption at 9 mo was not correlated with iron status but was significantly correlated with intake of dietary iron, including supplemental iron. CONCLUSIONS: Changes in the regulation of iron absorption between 6 and 9 mo enhance the infant's ability to adapt to a low-iron diet and provide a mechanism by which some, but not all, infants avoid iron deficiency despite low iron intakes in late infancy.     

彝、藏族青年男子膳食蛋白质吸收利用研究

目的　探讨、比较彝、藏族青年男子膳食蛋白质来源与人体吸收利用情况 ,为完善我国膳食蛋白质推荐摄入量提供基础数据。方法　以凉山彝族自治州和阿坝藏族羌族自治州两个学校的 18～ 2 2岁男子为受试对象 ,采用人体氮平衡试验 ,对其进行为期 14天的代谢试验 ,收集制备 9天的膳食、粪便和尿等样品 ,以半微量凯氏定氮法测定样品氮含量 ,计算分析蛋白质吸收利用指标。结果　彝族青年男子蛋白质摄入量为71 5 5g d ,蛋白质表观消化率为 73. 19% ,真消化率、生物价、净利用率的估算值分别为 79. 79%、4 7. 5 8%、38. 17% ,氮平衡为 0 . 71g d。藏族相应以上指标的数据为 94 . 33g d、86 . 6 9%、91 .4 3%、4 8. 0 7%、4 4. 0 0 %和3 .16g d。结论　藏族青年男子膳食蛋白质的供给与吸收利用状况优于彝族 ,但两者均能保持机体正氮平衡。     

Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet

BACKGROUND: Ascorbic acid has a pronounced enhancing effect on the absorption of dietary nonheme iron when assessed by feeding single meals to fasting subjects. This contrasts with the negligible effect on iron balance of long-term supplementation with vitamin C. OBJECTIVE: Our goal was to examine the effect of vitamin C on nonheme-iron absorption from a complete diet rather than from single meals. DESIGN: Iron absorption from a complete diet was measured during 3 separate dietary periods in 12 subjects by having the subjects ingest a labeled wheat roll with every meal for 5 d. The diet was freely chosen for the first dietary period and was then altered to maximally decrease or increase the dietary intake of vitamin C during the second and third periods. RESULTS: There was no significant difference in mean iron absorption among the 3 dietary periods despite a range of mean daily intakes of dietary vitamin C of 51-247 mg/d. When absorption values were adjusted for differences in iron status and the 3 absorption periods were pooled, multiple regression analysis indicated that iron absorption correlated negatively with dietary phosphate (P = 0.0005) and positively with ascorbic acid (P = 0.0069) and animal tissue (P = 0.0285). CONCLUSIONS: The facilitating effect of vitamin C on iron absorption from a complete diet is far less pronounced than that from single meals. These findings may explain why several prior studies did not show a significant effect on iron status of prolonged supplementation with vitamin C.     

Effects of resistant starch RS4 on magnesium and iron absorption in Wistar rats

The effect of resistant starch RS4 on apparent absorption of magnesium and iron was studied in Wistar rats. The rats (4 groups male n=12 and 4 groups female n=12) were fed for 4 weeks diets: control with wheat starch (K) and 3 diets with modified resistant starches (S1, S2, S3). After an adaptation period (14 d), rats were transferred to metabolic cages. Dietary intake and faeces were monitored for 3 days. Mg and Fe levels were assessed in diets and feces by atomic absorption spectrometry. Apparent absorption of minerals was calculated as mineral intake minus fecal excretion and expressed as persentage of intake. Our results confirmed that Mg apparent absorption in female rats fed diet with resistant starch S2 was significantly increased (+37%) compared with the control group.